Disconect from network,unplug the cable of your network.
Enter in Safe Mode and uninstall the old driver (or else ) with DDU.Use CCleaner,Tuneup Registry cleaner (or else) to clean the registry.Restart.
Enter in normal Windows and install the new driver.Restart.
Plug the network cable.
Enjoy gaming.

I just woke up about a hour ago (The time difference between whenever and here in Sweden usually means driver releases happen a bit after midnight.) but once these are installed I'll do the usual "atiapfxx.exe -r -sys -s test.xml" dump and comparison with 16.9.1-September 13
(Will dump a test.xml file in the syswow or what it was called folder which I then just do a quick comparison with against the previous dump.)

EDIT: Also copied over the Vulkan 1.0.26.0 runtime from the Nvidia driver, could take it from the SDK itself but the Nvidia driver was easily extracted with just Winrar instead of having to install a full SDK.
(Likely won't do much and I only really have two Vulkan games those being Talos Principle and DOOM-4 and none of those would be using the newer SDK, DOOM in particular hasn't had a patch in weeks now so I guess they're either OK with how it works or they're waiting on further DLC content before patching the game again.)

Tomb Raider had a profile added (Rise of the Tomb Raider or Tomb Raider 2013?)

That's about it, further down in the .xml there's additions linking these profiles to actual exe names such as Dreadnought being linked to DreadGame-Win64-Shipping.exe which should make it a UE4 game as those usually follow that naming schedule by default.

No major changes but the Crossfire flag changes might help with either performance or compatibility (Or both?) for the games they're for although in the case of Deus Ex Mankind Divided I don't know if it'll help for DirectX 12 or if that's now in the hands of the developers when working with this lower-level API.
(Might be what is making multi-GPU support lag behind for AMD and Nvidia GPU's in D3D12 if so, can imagine that supporting SLI is different from Crossfire even if the API might help streamline things a bit by standardizing some of this.)

OpenGL freesync should be useful too if that isn't already supported, particularly for Linux and well there's a few Windows games using OpenGL over Direct3D also with DOOM(4) being the most recent though AMD's not-quite-stellar OpenGL support makes Vulkan a more attractive choice for that game.
(And unlike DirectX 12 Vulkan isn't tied down to a particular OS either.)

The issue I was having with the new drivers not recognizing the Club3D 4k60hz adapter on 4K@60hz TVs, has a solution. For people having the same problem as myself with the new 16.9.x drivers (probably very few people here, but I thought I would just mention it anyways), you now have to make sure that you TV is in UHD HDMI deep color mode, in previous driver activating this mode rendered the adapter useless. So i'm guessing AMD must have changed something regarding the chroma with the new drivers.

Fallout is living up to it's name, falling out straight back to the desktop!

Are you sure he issue is driver related, and not system? Some overclocks can cause instability with different drivers, as the drivers can use the card in different ways. It doesn't mean your card or system was 'perfectly stable' with the overclock on older drivers, it just means the unstable part of the graphics card was likely underutilised and newer drivers manage to trip the overclock instability.